assume cs:codesg
datasg segment
    db "Beginner's All-purpose Symbolic Instruction Code.",0
datasg ends
codesg segment
    begin: mov ax,datasg
           mov ds,ax
           call letterc
           mov ax,4c00h
           int 21h
  letterc: mov si,0
           mov ch,0
      ss1: mov cl,ds:[si]
           jcxz s2
           cmp byte ptr ds:[si],97
           jb s1
           cmp byte ptr ds:[si],122
           ja s1
           sub byte ptr ds:[si],32
       s1: inc si
           jmp short ss1
       s2: ret

codesg ends
end begin
